Yanmar 6LY3-STC Operation Manual page 62

PERIODIC MAINTENANCE
Adjust Alternator V-Belt Tension
When there is not enough tension in the V-
belt, it will slip and the freshwater pump will
fail to supply coolant. Engine overheating
and seizure will result.
When there is too much tension in the V-belt,
the belt will become damaged more quickly
and the freshwater pump bearing may be
damaged.
WARNING! Perform this check with
engine off and key removed to avoid
contact with moving parts.
NOTICE: NEVER get any oil on the belt(s).
Oil on the belt causes slipping and
stretching. Replace the belt if it is damaged.
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1. Check the tension of the V-belt by
pressing on the middle of the belt
(Figure 6, (1)) with your finger.
With moderate force, the V-belt should
deflect 8 - 10 mm (approximately 3/8 in.).
2. If the V-belt deflection is out of the limit,
adjust the V-belt tension. Loosen the
adjuster bolt (Figure 6, (2)) and move
the alternator (Figure 6, (3)) to adjust
the V-belt tension.
3. If the V-belt is damaged or worn, replace
it. Loosen the adjuster bolt
(Figure 6, (2)) and move the alternator
(Figure 6, (3)). Remove belt from
pulleys.
4. Install new belt per routing (Figure 6)
and adjust the tension as shown in Step
2.
6LY3 LDC Operation Manual
© 2008 Yanmar Marine International
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0002077A
Figure 6
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